File size: 6,986 Bytes
fb5e185
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
import math
from dataclasses import dataclass
from typing import List, Optional, Union

import numpy as np
import torch
import torch.nn.functional as F
# import trimesh


from PIL import Image
from torch import BoolTensor, FloatTensor

LIST_TYPE = Union[list, np.ndarray, torch.Tensor]


def list_to_pt(

    x: LIST_TYPE, dtype: Optional[torch.dtype] = None, device: Optional[str] = None

) -> torch.Tensor:
    if isinstance(x, list) or isinstance(x, np.ndarray):
        return torch.tensor(x, dtype=dtype, device=device)
    return x.to(dtype=dtype)


def get_c2w(

    elevation_deg: LIST_TYPE,

    distance: LIST_TYPE,

    azimuth_deg: Optional[LIST_TYPE],

    num_views: Optional[int] = 1,

    device: Optional[str] = None,

) -> torch.FloatTensor:
    if azimuth_deg is None:
        assert (
            num_views is not None
        ), "num_views must be provided if azimuth_deg is None."
        azimuth_deg = torch.linspace(
            0, 360, num_views + 1, dtype=torch.float32, device=device
        )[:-1]
    else:
        num_views = len(azimuth_deg)
    azimuth_deg = list_to_pt(azimuth_deg, dtype=torch.float32, device=device)
    elevation_deg = list_to_pt(elevation_deg, dtype=torch.float32, device=device)
    camera_distances = list_to_pt(distance, dtype=torch.float32, device=device)
    elevation = elevation_deg * math.pi / 180
    azimuth = azimuth_deg * math.pi / 180
    camera_positions = torch.stack(
        [
            camera_distances * torch.cos(elevation) * torch.cos(azimuth),
            camera_distances * torch.cos(elevation) * torch.sin(azimuth),
            camera_distances * torch.sin(elevation),
        ],
        dim=-1,
    )
    center = torch.zeros_like(camera_positions)
    up = torch.tensor([0, 0, 1], dtype=torch.float32, device=device)[None, :].repeat(
        num_views, 1
    )
    lookat = F.normalize(center - camera_positions, dim=-1)
    right = F.normalize(torch.cross(lookat, up, dim=-1), dim=-1)
    up = F.normalize(torch.cross(right, lookat, dim=-1), dim=-1)
    c2w3x4 = torch.cat(
        [torch.stack([right, up, -lookat], dim=-1), camera_positions[:, :, None]],
        dim=-1,
    )
    c2w = torch.cat([c2w3x4, torch.zeros_like(c2w3x4[:, :1])], dim=1)
    c2w[:, 3, 3] = 1.0
    return c2w


def get_projection_matrix(

    fovy_deg: LIST_TYPE,

    aspect_wh: float = 1.0,

    near: float = 0.1,

    far: float = 100.0,

    device: Optional[str] = None,

) -> torch.FloatTensor:
    fovy_deg = list_to_pt(fovy_deg, dtype=torch.float32, device=device)
    batch_size = fovy_deg.shape[0]
    fovy = fovy_deg * math.pi / 180
    tan_half_fovy = torch.tan(fovy / 2)
    projection_matrix = torch.zeros(
        batch_size, 4, 4, dtype=torch.float32, device=device
    )
    projection_matrix[:, 0, 0] = 1 / (aspect_wh * tan_half_fovy)
    projection_matrix[:, 1, 1] = -1 / tan_half_fovy
    projection_matrix[:, 2, 2] = -(far + near) / (far - near)
    projection_matrix[:, 2, 3] = -2 * far * near / (far - near)
    projection_matrix[:, 3, 2] = -1
    return projection_matrix


def get_orthogonal_projection_matrix(

    batch_size: int,

    left: float,

    right: float,

    bottom: float,

    top: float,

    near: float = 0.1,

    far: float = 100.0,

    device: Optional[str] = None,

) -> torch.FloatTensor:
    projection_matrix = torch.zeros(
        batch_size, 4, 4, dtype=torch.float32, device=device
    )
    projection_matrix[:, 0, 0] = 2 / (right - left)
    projection_matrix[:, 1, 1] = -2 / (top - bottom)
    projection_matrix[:, 2, 2] = -2 / (far - near)
    projection_matrix[:, 0, 3] = -(right + left) / (right - left)
    projection_matrix[:, 1, 3] = -(top + bottom) / (top - bottom)
    projection_matrix[:, 2, 3] = -(far + near) / (far - near)
    projection_matrix[:, 3, 3] = 1
    return projection_matrix


@dataclass
class Camera:
    c2w: Optional[torch.FloatTensor]
    w2c: torch.FloatTensor
    proj_mtx: torch.FloatTensor
    mvp_mtx: torch.FloatTensor
    cam_pos: Optional[torch.FloatTensor]

    def __getitem__(self, index):
        if isinstance(index, int):
            sl = slice(index, index + 1)
        elif isinstance(index, slice):
            sl = index
        else:
            raise NotImplementedError

        return Camera(
            c2w=self.c2w[sl] if self.c2w is not None else None,
            w2c=self.w2c[sl],
            proj_mtx=self.proj_mtx[sl],
            mvp_mtx=self.mvp_mtx[sl],
            cam_pos=self.cam_pos[sl] if self.cam_pos is not None else None,
        )

    def to(self, device: Optional[str] = None):
        if self.c2w is not None:
            self.c2w = self.c2w.to(device)
        self.w2c = self.w2c.to(device)
        self.proj_mtx = self.proj_mtx.to(device)
        self.mvp_mtx = self.mvp_mtx.to(device)
        if self.cam_pos is not None:
            self.cam_pos = self.cam_pos.to(device)

    def __len__(self):
        return self.c2w.shape[0]


def get_camera(

    elevation_deg: Optional[LIST_TYPE] = None,

    distance: Optional[LIST_TYPE] = None,

    fovy_deg: Optional[LIST_TYPE] = None,

    azimuth_deg: Optional[LIST_TYPE] = None,

    num_views: Optional[int] = 1,

    c2w: Optional[torch.FloatTensor] = None,

    w2c: Optional[torch.FloatTensor] = None,

    proj_mtx: Optional[torch.FloatTensor] = None,

    aspect_wh: float = 1.0,

    near: float = 0.1,

    far: float = 100.0,

    device: Optional[str] = None,

):
    if w2c is None:
        if c2w is None:
            c2w = get_c2w(elevation_deg, distance, azimuth_deg, num_views, device)
        camera_positions = c2w[:, :3, 3]
        w2c = torch.linalg.inv(c2w)
    else:
        camera_positions = None
        c2w = None
    if proj_mtx is None:
        proj_mtx = get_projection_matrix(
            fovy_deg, aspect_wh=aspect_wh, near=near, far=far, device=device
        )
    mvp_mtx = proj_mtx @ w2c
    return Camera(
        c2w=c2w, w2c=w2c, proj_mtx=proj_mtx, mvp_mtx=mvp_mtx, cam_pos=camera_positions
    )


def get_orthogonal_camera(

    elevation_deg: LIST_TYPE,

    distance: LIST_TYPE,

    left: float,

    right: float,

    bottom: float,

    top: float,

    azimuth_deg: Optional[LIST_TYPE] = None,

    num_views: Optional[int] = 1,

    near: float = 0.1,

    far: float = 100.0,

    device: Optional[str] = None,

):
    c2w = get_c2w(elevation_deg, distance, azimuth_deg, num_views, device)
    camera_positions = c2w[:, :3, 3]
    w2c = torch.linalg.inv(c2w)
    proj_mtx = get_orthogonal_projection_matrix(
        batch_size=c2w.shape[0],
        left=left,
        right=right,
        bottom=bottom,
        top=top,
        near=near,
        far=far,
        device=device,
    )
    mvp_mtx = proj_mtx @ w2c
    return Camera(
        c2w=c2w, w2c=w2c, proj_mtx=proj_mtx, mvp_mtx=mvp_mtx, cam_pos=camera_positions
    )